Description
Mestrado em Engenharia do Ambiente - Instituto Superior de Agronomia The objective of this master thesis was to evaluate the effect of biochar on CO2 emissions from agricultural soil. The biochars were produced from three different feedstocks (clean pine chips, peanut hull and poultry manure) and at two different slow pyrolysis temperatures (400 ºC and 500 ºC).
Biochar properties were significantly influenced by the feedstock and pyrolysis conditions. The biochar yield was higher at lower pyrolysis temperature.
In general, biochar produced from woody plants had higher carbon (C) content, low nitrogen (N) content and low cation exchange capacity (CEC). Biochar produced from manure has low C content, high N content and CEC. The pH of these biochars ranged from neutral to alkaline.
To examine the effects of biochar on soil GHG production, an incubation experiment was performed. The emissions of CO2 in soils with biochar were evaluated through C mineralization. The biochar produced at 400 ºC by using peanut hull and poultry manure had a higher CO2 emission compared to that obtained at 500 ºC from raw materials.
The C mineralization was strongly controlled by the pyrolysis temperature than by the feedstock type.